1. Field of the Invention
This document relates to a liquid crystal display.
2. Description of the Related Art
As the information technology is developed, the market for display devices used as connection mediums between users and information is growing. Accordingly, the use of flat panel displays (FPDs) such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and a plasma display panel (PDP) is increasing. The liquid crystal displays have been widely used because they can implement a high resolution and can achieve both the small-sized screen and the large-sized screen.
The liquid crystal display comprises a transistor substrate, on which thin film transistors, storage capacitors, pixel electrodes, etc. are formed, a color filter substrate on which color filters, black matrixes, etc. are formed, and a liquid crystal layer positioned between the transistor substrate and the color filter substrate. The liquid crystal display adjusts an arrangement direction of the liquid crystal layer by an electric field generated between the pixel electrodes and common electrodes on the transistor substrate or color filter substrate, thereby displaying an image using light coming from a backlight unit.
In the liquid crystal display, the difference between a data voltage supplied from a data driver and a common voltage serving as a reference potential is applied as a voltage for driving the liquid crystals. The common voltage varies with the position of the liquid crystal panel due to the electrical resistance of a wire, capacitor, etc formed on the liquid crystal panel. For this reason, the common voltage becomes one of the voltages having the biggest effect on picture quality across the liquid crystal panel.
To prevent variations in common voltage, a compensation structure was conventionally suggested, which comprises a common voltage generator for generating a common voltage and a compensation circuit and receives a feedback common voltage from common voltage lines on two sides of the liquid crystal panel and compensates the common voltage supplied to the entire liquid crystal panel based on the feedback common voltage. In the conventional compensation structure, however, these variations are compensated for on the two sides of the liquid crystal panel, which makes it difficult to compensate for signal distortions caused by line resistance and coupling and brings about picture quality problems such as horizontal crosstalk that should be overcome.